The intradecadal fluctuations in the length‐of‐day variation (∆LOD) are considered likely to play an important role in core motions. Two intradecadal oscillations, with ∼5.9 and ∼8.5 years periods (referred to as SYO and EYO, respectively), have been detected in previous studies. However, whether the SYO and the EYO have exhibited stable damping trends since 1962 and whether geomagnetic jerks are possible excitation sources for the SYO/EYO are still debated. In this study, based on different methods and different ∆LOD records with different time spans, we showed robust evidence to prove that the SYO and the EYO have had no stable damping trends since 1962. We also found that there may be a ∼7.6 years signal, but given that its average amplitude is too small, further confirmations are needed in the future. After confirming that the jerks have no special consistency with the peaks/valleys of the EYO/SYO, we further used a deconvolution process and confirmed that the geomagnetic jerks seem to be related to sudden changes in the SYO/EYO time series and their excitation series. Thus we finally suggest that jerks are possible excitation sources of the SYO/EYO. After using a deconvolution process, we estimate that the period P and quality factor Q of the SYO and the EYO are [P = 5.85 ± 0.06 years, Q ≥ 180] and [P = 8.45 ± 0.17 years, Q ≥ 350], respectively.

中文翻译：

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日间变化中Intradecadal周期信号波动特征的新证据

日间变化量（∆LOD）的intradecadal波动可能在核心运动中起重要作用。在先前的研究中，发现了两次行业内振荡，周期分别为5.9年和8.5年（分别称为SYO和EYO）。然而，自1962年以来SYO和EYO是否表现出稳定的阻尼趋势，以及地磁急动是否可能成为SYO / EYO的激励源。在这项研究中，基于不同的方法和不同的ΔLOD记录以及不同的时间跨度，我们提供了有力的证据来证明SYO和EYO自1962年以来就没有稳定的阻尼趋势。我们还发现可能存在7.6年左右的时间。信号，但由于其平均振幅太小，将来需要进一步确认。在确认抽搐与EYO / SYO的峰/谷没有特别的一致性之后，我们进一步使用了反褶积过程，并确认地磁抽搐似乎与SYO / EYO时间序列及其激发序列的突然变化有关。因此，我们最终建议，抽搐可能是SYO / EYO的激发源。在使用反卷积过程后，我们估计P和品质因数Q的SYO和EYO的是[ P  = 5.85±0.06年，Q  ≥180]和[ P  = 8.45±0.17年，Q  ≥350]中。